Door latch assembly

ABSTRACT

A latch mechanism for a vehicle door having a pair of pivoted counterswinging latch elements adapted to be held in latched engagement with a striker pin by a detent means. Upon release of the detent means by a latch mechanism operator, the latch elements are free to move to an unlatched position permitting the vehicle door to be opened. The detent means is biased to be restored into engagement with the latch elements after release of the actuating means. Normally, under the biasing force, the detent means maintains an abutting relation to the peripheral surfaces of the respective latch elements and then moves further into latch element holding position as the latch elements encompass the striker. One of the latch elements is provided with an abutment on its peripheral surface positioned to engage a cam surface on a lever arm of the detent means to drive the latter into such latch element holding position in the event the normal biasing means becomes ineffective to do so for any reason.

Unite States Schlichter atent [54] DOQR LATCH ASSENELY [72] Inventor:William L. Schlichter, Livonia, Mich. [73] Assignee: Ford Motor Company,Dearbom, Mich. [22] Filed: Dec. 4, 1970 [2l] App]. No.: 95,221

52] user. ..292/48, 292/216, 292/010. 27, 292/010. 65 51 mo: ..E05c 3/26[58] Field of Search ..292/2l0, 45, 48, 216, 280, 292/DIG. 26, DIG. 27,DIG. 49, DlG.65

[56] References Cited UNITED STATES PATENTS 3,347,584 10/1967 Johnstone..292/216 X 3,561,807 2/1971 Ploughman ..292/2l6 FOREIGN PATENTS 0RAPPLICATIONS 67,241 6/1957 France ..292/49 [151 3,666,305 1 May 30, 1972Primary Examiner-Richard E. Moore Attorney-John R. Faulkner and John J.Roethel 57] ABSTRACT A latch mechanism for a vehicle door having a pairof pivoted counterswinging latch elements adapted to be held in latchedengagement with a striker pin by a detent means. Upon release of thedetent means by a latch mechanism operator, the latch elements are freeto move to an unlatched position permitting the vehicle door to beopened. The detent means is biased to be restored into engagement withthe latch elements after release of the actuating means. Normally, underthe biasing force, the detent means maintains an abutting relation tothe peripheral surfaces of the respective latch elements and then movesfurther into latch element holding position as the latch elementsencompass the striker. One of the latch elements is' provided with anabutment on its peripheral surface positioned to engage a cam surface ona lever arm of the detent means to drive the latter into such latchelement holding position in the event the normal biasing means becomesineffective to do so for any reason.

7 Claims, 7 Drawing Figures PATENTEDMAY30 m2 3,666,305

sum 30F s INVEN TOR.

noon LATCH ASSEMBLY BACKGROUND OF THE INVENTION The conventional vehicledoor latch mechanism comprises an assembly of pivoted latch elements,pivoted detent means for holding the latch elements in latchedcondition, pivoted levers for actuating the detent means to disengagethe latter from the latch elements to permit unlatching movement andvarious springs to bias the various pivoted members in the relativedirections of movement required to achieve the desired functions. Thedetent means in particular is springurged in latch element engagingdirection.

For any one of a number of reasons, the spring acting on the detentmeans may fail to bias the latter back into holding position relative tothe latch elements after disengagement therefrom. For example, thespring itself may fail, a corrosion buildup between the detent means andsupport plate may create excessive friction which the spring is unableto overcome or an ice coating between the detent means and support platecould interfere with proper operation.

Accordingly, it is an object of the present invention to provide a latchmechanism incorporating a latch element movement responsive means forpositively driving the detent means into latch element holding positionupon movement of the latch elements to latched position.

SUMMARY OF THE INVENTION The present invention relates to a latchmechanism comprising a primary support plate for disposition on theinner surface free edge wall of a vehicle door. The latch mechanism hasa secondary support plate in spaced parallel relation to the primarysupport plate. Mounted on the side of the primary support plate facingthe secondary support plate is a latch device means comprising a pair oflatch elements each mounted on a respective pivot shaft forcounterswinging movement into and out of latched position. A detentmeans comprising a lever member having a plurality of lever arms ispivotally mounted on a primary support plate on the same side of thelatter as the latch device means. The detent means has an arm havingspaced detent portions adapted to simultaneously engage spaced abutmentson the latch device elements to hold the latter against counterswingingmovement from latched to unlatched position. A spring means engaged withthe detent means normally urges the latter toward latch element holdingposition. The latch mechanism includes a cam means responsive tomovement of the latch device means toward latched position, as occursupon engagement of the latch elements with a striker as the door ismoved to closed position. This cam means positively biases the detentmeans into latched element holding position if the spring means fails todo so.

In particular, the cam means comprises a cam surface on a second leverarm of the detent means. The cam surface underlies the peripheralsurface on one of the latch elements. The one latch element has anabutment positioned to engage the cam surface to drive the detent meansinto latch element holding position.

The latch mechanism also has various members for actuating the detentmeans to disengage the latter from the latch elements and also to renderat least the outside operator inoperative to release the detent means.

DESCRIPTION OF THE DRAWINGS Further features and advantages of thepresent invention will be explained in greater detail making referenceto the description which now follows, reference being had to thedrawings in which:

FIG. 1 is a fragmentary perspective view of a vehicle body and a vehicledoor, parts of the door being cut away to expose the latch mechanism;

FIG. 2 is a plan view of the latch mechanism with a major portion of thecover plate or secondary support plate cut away to expose the latchmechanism components;

FIG. 3 is a plan view in part sectional of the primary support plate ofthe latch mechanism with the latch mechanism components mounted thereonshown in unlatched condition;

FIG. 4 is a plan view of the inner side of the cover plate or secondarysupport plate with the components of the latch mechanism mountedthereon;

FIG. Sis a diagrammatic view of the latch elements and the detent meansas they appear when the latch mechanism is in a secondary latchedcondition;

FIG. 6 is a view in part similar to FIG. 5 illustrating the latchelements and the detent means in fully latched condition; and

FIG. 7 is a view in part similar to FIG. 5 illustrating the latchelements in unlatched condition and the detent means as it appears afterbeing actuated for disengagement from the latch elements but before itis biased toward and restored in latch element engaged position by thespring means acting thereon.

DETAILED DESCRIPTION OF THE INVENTION Referring now to the drawings, thelatch mechanism, generally designated 10, is adapted to be mountedwithin a vehicle door 11 of a vehicle body. The latch mechanism isadapted to engage a striker pin 12 carried on the jamb face 13 of avehicle body panel 14.

The latch mechanism 10 has a primary support plate 15 which is adaptedto be secured by bolts (not shown) to the inner surface of the free edgewall 16 of the door 1 1. Threaded bolt receiving holes 17 are visible inthe FIG. 3 view of the primary support plate 15. The latch mechanism hasa secondary support plate 18 which is in spaced parallel relation to theprimary support plate 15. The two plates 15 and 18 are held in spacedparallel relationship to each other by side flanges l9 and 21 on theplate 15 and a top flange 22 on the plate 18.

The operating components of the latch mechanism are located between theprimary and secondary support plates 15 and 18. Some of these componentsmay be considered as primarily mounted on the inner side of the primarysupport plate 15. These include the latch device means which comprises apair of latch elements 23 and 24. The latch elements 23 and 24 areirregularly shaped plates which are pivotally mounted on respectivepivot shafts 25 and 26, the axes of which project in a direction normalto the support plate 15. Each pivot shaft 25 and 26 is riveted at one ofits ends to the plate 15 and in final assembly at its other end to theplate 18 thereby functioning to hold the support plates in assembledrelationship as well as providing for pivotal support of the latchelements.

The latch elements are swingable in counterswinging directions and arevertically displaced relative to one another with overlapping portions.

Each latch element 23-24 has a semi-circular pin receiving notch 27adapted in door latched condition to encompass the striker pin 12carried in the body pillar jamb face 13. Each latch element has anextension or finger 28 at one side of the notch 27 which, as will beexplained with reference to FIG. 6 and 7, are adapted to overlie eachother to provide a barrier against relative unlatching movement betweenthe latch elements and the striker pin in door latched condition.Rearwardly of the extension or finger 28, each latch element has astraight peripheral surface 29 extending tangentially from a curvedsurface 31 which is interrupted by an abutment 32. The abutment 32 is astep to a further curved surface 33 of greater radius than the curvedsurface 31. The curved surface 33 is interrupted by a pair of spacedsteps or abutments 34 and 35. From the abutments 34 and 35 back to thenotch 27, each latch element has a substantially outwardly radiallyextending apex portion'36.

The side flange 21 of the primary support plate 15 is provided with anenlarged opening bounded by inwardly turned flanges 37 and 38. Theseflanges lead into a substantially V- shaped notch 39 in the primarysupport plate having flanged guide edges 41 and 42 for guiding thestriker pin 12 into proper alignment between the latch element notches25. The V-shaped notch 39 terminates in a rounded bight 43.

The latch elements are spring-urged in counter or opposite directionstoward unlatched position by a compound spring44 having counterwoundcoiled end portions 45 and 46 encompassing the respective pivot shafts25 and 26. The coiled portions 45 and 46 have free end portions 47 and48 hooked over the edge of the latch elements in engagement with therespective abutments 32. The spring coiled end portions bias the latchelements toward unlatched position to the extent permitted by stops 49and 51 in the side flange 21.

Cooperable with the abutments 34-35 on the latch elements 23-24 is aswinging detent means 52 pivotally mounted on a shoulder rivet 53secured to the primary support plate 15.

The detent means 52 is a plural armed lever member. A first one of thelever arms, the arm 54, extends from the pivot 53 generallylongitudinally of the primary support plate so as to lie to one side ofthe latch elements 23-24. The lever arm 54 has spaced abutments 55-56 onits latch element contiguous side which are adapted to coact with theabutments 34-35 on the latch elements, as will be further explained.

The second arm 57 of the detent means 52 extends generally transverselyof the primary support plate and lies in contiguous relationship to thelatch element 23. Intermediate its ends the arm 57 has a cam surface orabutment 58 which under certain conditions abuts the latch element 23peripheral surface 31, see FIG. 7.

The detent means 52 is spring-loaded in latch element engaging directionby a compression spring 59 which extends between a downwardly projectingarm 61 on the detent means and a tab 62 formed on the lower portion ofthe primary support plate 15.

The present latch mechanism is preferably operated from the inside ofthe vehicle door through the medium of a remote control mechanism (notshown) connected to a longitudinally shiftable draft link or rod 63which is pivotally connected to the lower end of a vertically dependingarm 64 of a bell crank 65. The bell crank 65 is pivoted on the shank ofa shoulder rivet 66 (See FIG. 2) secured to the primary support plate15. The bell crank 65 has a substantially horizontally extending arm 67adapted to underlie an extension 68 on the end of the detent means arm57. The shoulder rivet 66 on which the bell crank 65 is mounted issecured to a flange 69 which extends in a direction normal to thesurface of the primary support plate 15. Movement of the draft link 63in a direction toward the latch mechanism, i.e., in the direction of thearrow 71 in FIG. 1, causes the bell crank 65 to be swung to raise itsarm 67. This causes a lifting movement to be applied to the arm 57 ofthe detent means 52 causing the arm 54 of the latter to be swung awayfrom the latch elements.

Release of the detent means 52 from the latch elements 23-24 through theremote control mechanism on the inside of the vehicle door isindependent of the actuation of the detent means from the outside of thevehicle door.

The latch mechanism components for releasing the detent means from thelatch elements from the outside of the vehicle door are supported on thesecondary support or cover plate 18 and reference is now made to FIG. 4for the orientation of these components. As was noted above,disengagement of the detent means 52 from the latch elements 23-24 isaccomplished by swinging the detent means in a direction to cause thearm 54 to move away from the latch elements. This is accomplished fromthe outside of the vehicle door by a system of levers and links whichcomprise a bell crank lever 72 pivotally mounted on a shoulder rivet 73fastened to the secondary support plate 18. The bell crank lever 72 hasa generally horizontally extending arm 74 adapted to be connected by alink 75 to an outside operator (not shown). The bell crank lever 72 alsohas a generally vertically extending arm 76 which at its upper end has atab portion 77 which fits through a slot 78 in an elongated link 79.

The link 79 is pivotally supported at its upper end on a pivot stud 81carried on a generally horizontally extending member 82 which is pivotedintermediate its ends by a pivot stud 83 secured to the secondarysupport plate 18.

At its end opposite the pivoted end, the link 79 has a tab 84 which inunlocked condition of the latch mechanism 10 lies in abuttingrelationship to a flange 85 on the edge of the detent lever arm 54.Thus, when the bell crank lever 72 is swung in a counterclockwisedirection, as viewed in FIG. 2 the interconnection between the bellcrank lever 72 and the link 79 results in the latter also being swung ina counterclockwise direction. The tab 84 will then abut the flange 85and cause the detent means 52 also to be swung in a counterclockwisedirection away from and out of engagement with the latch elements 23-24.This permits the latch elements, if in a latched condition, to move toan unlatched condition so that the vehicle door may be opened relativeto the body panel.

If the member 82 is shifted about its pivot axis 83 in a clockwisedirection, the tab 84 on the end of the link 79 will bypass the flange85 on the detent means arm 54. This effectively renders the outsideoperator ineffective to disengage the detent means 52 from the latchelements 23-24. The latch mechanism then is considered in a locked"condition. The member 82 thus may be considered a locking controlmember.

The locking control member is shiftable about the pivot axis 83 from alatch mechanism locking position to a latch mechanism unlocking positionfrom either the inside or the outside of the vehicle door. As best seenin FIG. 1, the vehicle door is provided with a push button 86. Such abutton conventionally is accessible at the upper edge of the door insideof the window glass. The push button 86 is connected by a link 87 to anapertured appendage 88 on the locking control member 82. With the pushbutton 86 in a raised position as shown in FIG. 1, the locking controlmember 82 is in the normal latch mechanism operative position shown inFIGS. 2 and 4. In this position, as has been explained, the link 79 isswingable to cause the detent means to be disengaged from the latchelements.

The second locking link 89 is connected to the apertured end 91 of thelocking control member. The link 89 at its upper end is coupled to aconventional key cylinder mechanism through which the link may beshifted up and down to swing the locking control member about its pivotaxis 83.

The locking control member 82 is held in either latch mechanism lockedor latch mechanism unlocked position by a toggle spring 92 extendingbetween the control member 82 and the secondary support plate 18. Oneother spring of importance is a spring 93 which is mounted on thesecondary support plate 18 and urges the link 79 in a counterclockwisedirection as viewed in FIG. 4 out of abutting relation with the flange85 on the detent means arm 54. Every time the link 79 is actuated byactuation of the bell crank 72 it is restored to its inoperativeposition by the spring 93.

Referring now to FIGS. 4, 6 and 7, several different operativerelationships of the detent means to the latch elements are shown. InFIG. 5, for example, detent abutments 55 and 56 on the detent means arm54 are shown interposed between the abutments 34 on the latch elements23 and 24. In this condition the latch elements 23 and 24 are not intheir fully latched position. This occurs when insufiicient force isexerted on the door during closing movement to cause the striker pin, asit enters between the fingers 28 into abutting relation with the apexportions 36, to drive the latch elements toward a fully latchedcondition. In the FIG. 5 condition, the door is latched but is not heldfully against rattling or vibratory motion.

FIG. 6 illustrates the normal fully latched condition of the latchelements in which the abutments 55 and 56 on the detent means arm 54 areinterposed between the abutment surfaces 35 on the latch elements 23 and24. In this condition the striker pin 12 is tightly gripped by the latchelements so as to hold the door against movement in any direction.

In FIG. 7, the relationship of the detent means to the latch elementsmay be considered as that which occurs after the detent means 52 ismoved to a fully disengaged position relative to the latch elements byeither the inside or outside operator. The latch elements 23 and 24 areheld in their fully unlatched position by the compound spring 44. Thedetent means under the influence of spring 59 now should be restored toan abutting relationship to the latch elements, such as shown in FIG. 3.It will be noted in FIG. 3 that the comer edge of the abutment 55 on thedetent means arm 54 is in abutting relation to the curved edge 33 of thelatch element 23. Under the influence of the spring 59, upon the latchelements being moved toward latched condition the detent abutments 55and 56 should first move into the FIG. 5 relationship, and then, ifsufficient force is exerted on the door, into the final latched positionshown in FIG. 6.

For any of a number of reasons, such as the failure of spring 59 or theaccumulation of road dust, dirty grease or even an ice coating betweenthe detent means and the primary support latch plate 15, conditionscould arise in which the spring 59 is unable to urge the detent means52in a clockwise direction as viewed in FIG. 7. With the detent meansinhibited from movement from this position the door would rebound to anopen position since the detent means abutments 55 and 56 would notachieve either the FIG. 5 or the FIG. 6 relationship to the abutments onthe latch elements.

According to the present invention, the detent means arm 57 with its camsurface 58 lies in abutting relation to the peripheral surface 31 on thelatch element 23 so that as the latch element is swung in acounterclockwise direction upon engagement with the striker pin 12, theabutment 32 will engage and kick the cam surface 58 downwardly thusdriving the detent means 52 in a clockwise direction. The relationshipof the latch element abutment 32 to the cam surface 58 on the detentmeans arm 57 is such that this action occurs just as the latch elementabutments 35 are in a position of slight overtravel relative to oneanother so that the abutments 55 and 56 on the detent means arm 54 areable to position themselves between the latch element abutments 35.Thus, even if for any reason spring 59 is ineffective to accomplish itsfunction of restoring the detent means to normal latch element holdingposition, the interaction between the latch element 23, abutment 32 andthe cam surface means on the detent means arm 57 insures that thelatching relationship will be achieved.

It will be understood that the invention is not to be limited to theexact construction shown and described, but that various changes andmodifications may be made without departing from the spirit and scope ofthe invention as defined in the appended claims.

Iclaim:

I. A latch mechanism comprising:

a primary support plate for disposition adjacent an inner surface of afree edge wall of a vehicle door and a secondary support plate in spacedparallel relation to the primary support plate,

latch device means mounted on the side of the primary support platefacing the secondary support plate comprising a pair of latch elementseach mounted on a respective pivot shaft for counterswinging movementinto and out of latched position,

detent means comprising a lever member having a plurality of lever armsand pivotally mounted on the primary support plate on the same side ofthe latter as the latch device means,

a first one of the lever arms having spaced detent portions thereonadapted to simultaneously engage spaced abutments on the latch deviceelements to hold the latter against counterswinging movement fromlatched to unlatched position,

spring means engaged with and normally urging the detent means towardlatch device means holding position,

cam means responsive to movement of the latch device means to latchedposition for positively driving the detent means into latch elementholding position on failure of the spring means,

and detent actuating means on the surface of the secondary support platefacing the primary support plate operable to disengage the detent meansfrom the latch device means to permit latch element movement tounlatched position.

2. A latch device mechanism according to claim 1, in which: the cammeans for driving the detent means into latch element holding positioncomprises:

a second one of the lever arms having a cam surface thereon adapted inunlatched position of the detent means to underlie a peripheral surfaceof one of the latch elements,

and an abutment on the one latch element positioned to engage the leverarm cam surface to drive the detent means into latch element holdingposition.

3. A latch mechanism according to claim 2, in which:

the detent actuating means comprises an elongated detent engaging memberhaving a detent lever arm engaging abutment on one end,

a control lever pivotally mounted on the secondary support plate,

the detent engaging member being pivotally connected at its other end tothe control lever,

and an operating lever pivotally mounted on the secondary support plateand coupled to the detent engaging member for swinging the latter tocause the abutment thereon to engage the detent means and swing the sameout of latch device means engagement.

4. A latch mechanism according to claim 3, in which:

the control member is shiftable to move the detent engaging memberlongitudinally to displace its end abutment out of the path of thedetent actuating means thereby to render the latter inoperative todisengage the detent means from the latch elements.

5. A latch mechanism according to claim 4, in which:

a compound spring means has respective coiled end portions encompassingeach of the latch element pivot shafts,

each coiled end portion terminating in a free end engaging an abutmenton a respective latch element and exerting a torque thereon for urgingthe latch elements in unlatching direction,

and the free end of one coiled end portion is engaged with the abutmenton the one latch element positioned to engage the second lever arm camsurface.

6. A latch mechanism according to claim 2, in which:

a compound spring means has respective coiled end portions encompassingeach of the latch element pivot shafts,

and each coiled end portion terminates in a free end engaging anabutment on each latch element and exerting a torque thereon for urgingthe latch elements in unlatching direction.

7. A latch element according to claim 6, in which:

the free end of one coiled end portion is engaged with the abutment onthe one latch element positioned to engage the second lever arm camsurface.

1. A latch mechanism comprising: a primary support plate for dispositionadjacent an inner surface of a free edge wall of a vehicle door and asecondary support plate in spaced parallel relation to the primarysupport plate, latch device means mounted on the side of the primarysupport plate facing the secondary support plate comprising a pair oflatch elements each mounted on a respective pivot shaft forcounterswinging movement into and out of latched position, detent meanscomprising a lever member having a plurality of lever arms and pivotallymounted on the primary support plate on the same side of the latter asthe latch device means, a first one of the lever arms having spaceddetent portions thereon adapted to simultaneously engage spacedabutments on the latch device elements to hold the latter againstcounterswinging movement from latched to unlatched position, springmeans engaged with and normally urging the detent means toward latchdevice means holding position, cam means responsive to movement of thelatch device means to latched position for positively driving the detentmeans into latch element holding position on failure of the springmeans, and detent actuating means on the surface of the secondarysupport plate facing the primary support plate operable to disengage thedetent means from the latch device means to permit latch elementmovement to unlatched position.
 2. A latch device mechanism according toclaim 1, in which: the cam means for driving the detent means into latchelement holding position comprises: a second one of the lever armshaving a cam surface thereon adapted in unlatched position of the detentmeans to underlie a peripheral surface of one of the latch elements, andan abutment on the one latch element positioned to engage the lever armcam surface to drive the detent means into latch element holdingposition.
 3. A latch mechanism according to claim 2, in which: thedetent actuating means comprises an elongated detent engaging memberhaving a detent lever arm engaging abutment on one end, a control leverpivotally mounted on the secondary support plate, the detent engagingmember being pivotally connected at its other end to the control lever,and an operating lever pivotally mounted on the secondary support plateand coupled to the detent engaging member for swinging the latter tocause the abutment thereon to engage the detent means and swing the sameout of latch device means engagement.
 4. A latch mechanism according toclaim 3, in which: the control member is shiftable to move the detentengaging member longitudinally to displace its end abutment out of thepath of the detent actuating means thereby to render the latterinoperative to disengage the detent means from the latch elements.
 5. Alatch mechanism according to claim 4, in which: a compound spring meanshas respective coiled end portions encompassing each of the latchelement pivot shafts, each coiled end portion terminating in a free endengaging an abutment on a respective latch element and exerting a torquethereon for urging the latch elements in unlatching direction, and thefree end of one coiled end portion is engaged with the abutment on theone latch element positioned to engage the second lever arm cam surface.6. A latch mechanism according to claim 2, in which: a compOund springmeans has respective coiled end portions encompassing each of the latchelement pivot shafts, and each coiled end portion terminates in a freeend engaging an abutment on each latch element and exerting a torquethereon for urging the latch elements in unlatching direction.
 7. Alatch element according to claim 6, in which: the free end of one coiledend portion is engaged with the abutment on the one latch elementpositioned to engage the second lever arm cam surface.